20 
pi. VIII. fig. 1. but differs from it in the flatness of the keel, 
and in being provided with two ribs only to each tubercle ; 
and is distinguished from A . auritus , pi. VII. fig. 9> by the 
volutions being inserted. 
103. A. Bircii ir.—Birch’s Ammonite, pi. XIV. fig. 7. 
Ammonites Birchii. Sowerby, Min. Conch. III. p. 121, 
pi. 267. Fleming, Brit. An. p. 246 ; De la Beclie, Geo. 
Man. p. 374. 
Discoidal, with from six to eight wholly exposed, gradually 
increasing volutions ; sides concave, each volution ornamented 
with about thirty pairs of thin, obtuse tubercles, each pair 
united by a slightly elevated rib; back rounded with obscure 
sulci, which traverse the sides, on which, however, they are 
nearly obsolete; aperture transverse, its length being very 
little more than its breadth ; greatest diameter seven inches 
and a half. 
Found at Lyme Regis, Dorsetshire, by Colonel Birch, and 
named in honour of him: it also occurs at Charmouth and 
Cragmouth, and in the Lias in the middle and south of Eng¬ 
land. 
104. A. Goodiialli -Goodhall’s Ammonite, pi. XIV. 
fig. 10. 
Ammonites Goodhalli. Sowerby, Min. Conch. III. p. 100, 
pi. 255 ; Fleming, Brit. An. p. 243 ; De la Beche, Geo. 
Man. p. 296. 
Discoidal, carinated; with five ribbed, somewhat rapidly 
increasing volutions, the inner ones one*third inserted; both 
edges of the volutions gradually rounded ; sides nearly flat, 
and provided with large, broad, undulated, irregular, rather 
flat ribs, obscurely tubercnlate at both ends ; between the 
principal ribs, sometimes shorter ones intervene, these have 
tubercles at the outer ends only ; keel thin and very promi¬ 
nent ; aperture oblong, slightly compressed in the centre. 
Found at Blackdown, Devonshire, in the Lower Green¬ 
sand, by II. II. Goodhall, and named in honour of him. 
Mantell also records it as a fossil of the Lower Greensand of 
Sussex ; and in the same at Lyme Regis, according to De 
la Beche. 
105. A. Bennetianus -Rennet’s Ammonite, pi. XV. 
%. i. 
Ammo7iites Bennetianus . Sowerby, Min. Conch. VI. p. 77, 
pi. 539. Fleming, Brit. An. p. 248. De la Beche, Geo. 
Manuel, p. 295. 
Sub-globose, with from four to six rapidly increasing 
volutions, the inner ones partlv concealed, having a row of nine 
or ten large conical, blunted tubercles on each side, and a 
series of twenty very large obtuse tubercles invest each side 
of the back or ambit; these are connected by prominent, 
obtusely rounded ribs, which are stronger and more numerous 
between the series of tubercles than upon the inner sides of 
the volutions, and become quite obsolete upon the narrow 
space over the siphuncle; aperture transversely oblong. 
I 11 the very young state, the aperture is nearly circular, 
without any appearance of tubercles; but as it increases in 
dimensions, the aperture gradually becomes wider, and the 
tubercles begin to emanate from the ribs, and soon assume a 
produced aspect, those upon the sides being always the 
largest and most prominent. 
Found among the Tile Greensand Clay at Cockerton, near 
Warminster. 
106. A. tetrammatus. —The Four-Tubercled Ammonite, 
pi. XV. fig. 2. 
Ammonites. 
Ammonites tetrammatus , Sowerby, Min. Conch. VI. p. 166, 
pi. 587, fig. 2. De la Beche, p. 294. 
Discoidal, carinated, with four or five convex volutions 
crossed by numerous obscure furcated ribs, each furnished 
with four round, blunt tubercles, the external ones compressed, 
and two on the shorter branches; carina sharp and entire. 
This species bears a considerable resemblance to some of 
the varieties of Ammo7iites various , pi. VIII. more especially 
to that of fig. 5, in which there are some of the sets of 
tubercles in fours, but these are only towards the aperture, 
all the others being in pairs; the A. titrammatus is, besides, 
always a larger shell than the A. various , and has invariably 
four rows of tubercles. 
107- A. Vernoni. —Vernon’s Ammonite, pi. XV. fig. 3. 
Ammonites Vernoni , Phillips, Geo. Yorkshire, I. p. 138. 
pi. 5, fig. 19 . De la Beche, Geological Manuel, p. 370. 
Discoidal, with three or four rounded volutions, the inner 
ones nearly half inserted; the sides furnished with numerous 
elevated furcated ribs, which emanate from the inner sides of 
the volutions, and when they reach the centre, split into two 
branches of nearly equal thickness, and passing over the 
rounded back, meet and join those of the opposite side; 
aperture oblong. 
Discovered iti the Oxford Clay at Scarborough, by Mr 
Bean, and is also found in the same kind of strata at Ebber- 
ston, Lincolnshire. 
108. A. Williamson i. — Williamson’s Ammonite, pi. XV. 
fig. 4. 
Ammonites Williamsonu Phillips, Geology of Yorkshire, 
I. p. 131, pi. 4, fig. 19* De la Beche, Geo. Manuel, p. 370. 
Shell, with five or six thick, slightly raised volutions, the 
inner ones wholly exposed ; sides crossed by numerous 
straight, elevated, parallel ribs, which rise from the inner 
margin of the volutions, and pass continuously over the broad, 
flat, and thick ambit, and end on the inner margin of the 
volutions on the opposite side ; aperture oblong, nearly 
quadrangular. 
Found in the Coralline Oolite at Ayton, Yorkshire, by 
Mr Williamson, and named in honour of him by Professor 
Phillips. 
109* A. vittatus. —The Filleted Ammonite, pi. XV. fig. 5. 
A77i77io7iites vittatus . Phillips, Geology of Yorkshire, I. p. 
164, pi. 13, fig. 1 . De la Beche, Geo. Manuel, p. 372. 
Discoidal, carinated ; with four or five slightly raised 
volutions, the inner ones a third inserted; the sides crossed 
by numerous straight, slightly elevated ribs, which have a 
slight curvature forward at their outer extremity, and termi¬ 
nate on the side of the sharp, thin, and elevated carina, every 
rib provided with two tubercles, one at each extremity ; those 
on the inner side but slightly raised, and the outer ones 
round and well defined. 
Found in Calcareous Nodules in the Lias of Yorkshire, 
according to Young and Bird, and Professor Phillips. 
110. A. Gowerianus. —Gower’s Ammonite, pi. XV. fig. 6 . 
Ammonites Gowerianus . Sowerby, Min. Conch. VI. p. 94, 
pi. 549, fig. 2 . Phillips, Geology of Yorkshire, I. p. 141, 
pi. 6 , fig. 21, a variety. De la Beche, Geo. Manuel, p. 370. 
Compressed, deeply umbilicate; with six or seven convex 
volutions, the inner ones half inserted, deeply sunk below 
the level of the outer one; sides crossed by numerous 
elevated and sharp ribs, which take their rise from the inner 
edge of the volutions, and extending over half of the sides, 
MOLLUSCA. 
